SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2baf38d23777cf0709fe39892f2de3fb113a6f84999fff39eeea2196783e29ad' 
  AND token = 'x0RwoNl5ZFvzn3ELQzTzhyjB50YrS5biO+T313FomEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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