SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bd43e50e01801c235af2070486fd3993208a079816fd7e8059f32629cac2d76' 
  AND token = 'a+Nk5sPFsroTf9/7HBWeGdRZgjygVzZpN1h7eU+KQsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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