SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5870766bf875fb9ea1efcdcb31a388b7eda4a8bc4d293890f775c2c67aea9392' 
  AND token = 'joPUoj3WPcOiVq+ePEpdrLLa1lL96dUNbg9HSd1izwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}