SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a7b336095e4c66da0f2518ecdeb22bb6a21b6e36a1f3f7d6ee2589d8b19b212' 
  AND token = 'i5ZSHaKapK7AZO8qz8h3AUQ2W2L+eFYHGRzN85zO0wU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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