SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fb8d5347362a30256f17955d01007c184c35f59dd9e830411d65ea49922c2c3' 
  AND token = 'td6lDQ6aUzw0BVOWP69KCG08QrWmjSZhsXVaYZDYiUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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