SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73d226317a2b1325d672fece429112dd512ef29b9718a8b3dd97693649f0d787' 
  AND token = 'jJsITla6o5bbE5WuIK10Rm/tAE211ecb3lGiwLd79Mk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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