SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '427d8abca941cef7296518525238976531d32ac901e9ff05437b9fbec4bc4fed' 
  AND token = 'rXceXZhyT7hAGMthHyvDdFBp0Ivzz1PDv/Ft67TU3xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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