SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ac5fa5c33bea683f1fda66837b8a59c4a42af279218bee36404b8358be2409e' 
  AND token = 'uVQNa4rOceSrLX93dmxug6weQ9pT0ReRSUqCSoUnQv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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