SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8da7c75d73135640628320a21a0f52823cab4c7d5a175920c05ac688a527e8e0' 
  AND token = 'uqQIJbGywbtkwgb9NWHdJOEGceqTbIgbd1OlmtgjMac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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