SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8848db2cc6e05790da6a9850624cf83898921d000baabcd95297080fbc0cead' 
  AND token = 'lKp7cJKryAEjc14AiUFvk6YbAL4XA6Wpv/DKQdOGkpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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