SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6c2207bf1595f109410f82e403f553ce39d78dc4449113b91c5eb674016a2ded' 
  AND token = 'hTfVQ9AVu9BS+Z6xOO+vL8mnTuN0vZ8j8KrRqj02abY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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