SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7d642feff988d42093b1de5d8937ccadd76733f2ca638b22f10749d62ebb4ad5' 
  AND token = 'sZXzvZ1C8CgmsvY4JoechIedqB56otrnUoFD3rVIdOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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