SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59849b33f94f64d2f624cc5503678a787f067c611ae62263524db0e8da501f30' 
  AND token = 'tpXfS5mwgb4TnAs0NRupHuBh1ut4PJVjAjUxZShi0Ng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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