SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be50471914dc5654595901fcb53f02660cae654f1efcd7b265d4bc84bf9b1728' 
  AND token = 'Xslb2aAb8yrRdRr/XqXAxn2ZxeUGL1coL+Rt4ylkd1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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