SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8419c3578af71bff6fd24a3dcf5f294bb1d621becb00ca02d2221daa55039aa0' 
  AND token = 'HZLV3m6mUDZCCrCJlvsNVvdKeeUf7G8FPhoc+UoD1/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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