SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bed77536f028c0c8c2d58f5e59664eeec05eddb43cb76fe0d3870afcaeb2c685' 
  AND token = 'p+8FLA8NBNqxmTvrzLhvXWlVB5geSepawRF89LA5StM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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