SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd85abba748589e7ea21fe94dfc285544ab0c05298b7d5e9813c477dacd0e2df7' 
  AND token = 'NpF9obTPgWLqyHUkr0pKkljZJmg+fGsQY4CBCk2vQ4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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