SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57380d096da75cbaba63158dd774d37efbece0dc71b433251dfbb1354207f807' 
  AND token = 'r7zKuZboYGNWLkkYfZlNF2bL5lnfPmjevrbwJUVZgq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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