SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f82a182c2c38f6c464ada01b9a1bba85e448d8f70b0989f423bda78deff93763' 
  AND token = 'eruUL6mkTU+jlTGnVj3dokD+nH8/HCudpeKxHxNqpvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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