SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12f2fa86b241a4d0d4d3c750e0f06069389dbe7a37acd7c458a29a6105650fb5' 
  AND token = 'JGvahZomMfyEcoMVq+wp01ygVVzwSlLEB6de0/SV1KQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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