SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '639656001e788b46aeceb5755cb66afa37301b80dfa76a4f44e4a6bcd0b39fd1' 
  AND token = 'X/g7ZNZl55+lOk2BEUG+3davUAGsXwMNk0GPqbzZ/hk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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