SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de700833099966b9360d17c2c166ae9949342e26d1b376fe9b9416a81a1a61cd' 
  AND token = '6qDhKkyzeQ+YxQQSvPoe4twEgVkJ6+xkw/X78KmWaDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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