SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7eef4492d508a56060e9459775601fdb6e159cd4f15f4d4bc97d443bff7738b2' 
  AND token = 'ieBIsSCZPPSzvqQfH/QOtV5cz4d5kLu2Pp+5JT+Y90Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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