SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36ad8d77386076b93325f1753b0e40e777e67c5bc7e19f425785cf3978aebc45' 
  AND token = '8+CIEGV4/qnkhDFmkNMlZQTdqz64KVwqxV4W6RoY0R4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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