SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c176e1e35ed43dd2c0e9b6e7517667098467a89b31b2d2da720fa0f553b5e25b' 
  AND token = 'gQZCEUu9WnJdiPBIhbwgez9YbdK5zXIVJFqMKEYXvG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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