SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '681db4e51ee376d4bb97ebca25aec1586210fab653f98910e39eca0669959e59' 
  AND token = '8uEiDSTcyB2zrTks1YrYwpPqVdBA/r23oT/s23iljwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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