SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50b3245698cdd5717afee333772aa6135b894cc299190bdc3e223477d17ef7cc' 
  AND token = 'IC2fnNQ05J7FDsEsokMygcxE6rk8bze+NAITrT7dZG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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