SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dbf8777d33d24e44fdce21371eec302691d50ecde7e6a800089fc7c12df72a40' 
  AND token = 'QF51Gq2PtFqZXzXVAoPipZszOQUm2CiSAeByW2JpL1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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