SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fde4d763ae21f43e052d370e789d408ad3f4323f42c8fab1b0e0b114cf6ba437' 
  AND token = 'A7tw/4oIjR6pmrLXlsM5JBL3Nd3XOE6rlFlsa55EfrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}