SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'aa906b62e51e18397bf5b199cd5798f286a06e88fa7c50ab23f8999e68db51ae' 
  AND token = 'LNa+P55HHNy8Nac+5uMx+ktfp19q2w3ZsLnFW80nnk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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