SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2c6d9bd5f9e80dd41919606092d565d40e69d8c755bbe6069d0561cdd29984a' 
  AND token = 'LrR2wZCZpe3et54CHOj1TKWHEngHHY/whLrXTQXK5mM=' 
  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"
    }
  }
}