SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '575b44d984a9d7d46b590a1f693f22e9e265a61230c50a358d7c56f6009d1281' 
  AND token = 'h9VE7frUp3RD5Yy4Vu1Gqcr0kqQEGrjHIYILJ5eb03g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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