SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f344c00628d76da28a7d003defd36672a4d7017ed64d7c564365149841507dba' 
  AND token = 'Atjz9lhIG2v9NQwLy6PhSkK4QMTmt+fN9A9Zhps92Lo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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