SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb96fab2df09af030fca055db8db50b4b4245c16d5c4b348249c13568f4e9d43' 
  AND token = '8eWY/MGoH/vg/GCsoWy0H/LwwlpqV7xCaZwC78ajx1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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