SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '787c666c55758e9038aa17725fbd1a2d936d400b4a5a09db0f2e8b9bba4d83fb' 
  AND token = '1SdAGPlpX9U1+EfrzhUV6AJenIHeEcsA0Enud9IXb2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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