SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc0e2eb4dda9ebb87ad15fa18143db3e1338f1575581e4941916752ac5a13c80' 
  AND token = 'h5xyH5TB5DV7qqDBV9x31heR4rvPPDAqR7e8H/eMYh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}