SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1f1850d74c644114e098661dba8bd96d153be42dd9619effb8707e26afc9a21' 
  AND token = 'qwss2Ig4BzYvQV5MNB/1OtycQtKwqLzbjI4bvsDcZmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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