SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '343a6c6f26877271e93d52016d9debac6f6a98f319171b6653377ffd1a69dc27' 
  AND token = 'vRBqN1FUhcXqsG2+/5X9glgk0At9JD9yjzRfL6oHKqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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