SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe5ecad412288e905c01ee642641a41902967a1e7ce416778edb5168bd105711' 
  AND token = 'B/I+79TcRYLTwbvKbAzO+arcym2qhjIbx1JO7AVvdFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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