SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e51532d419d8e9761bf530a76752cbbe06cb06aeaabe9a2e3240d01034fecf0' 
  AND token = 'RTJUjaZOvfhL0siSVkg8u6ULthI7jGa5PrlqHwElEXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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