SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4269ba69c22604f235a673fcd92e4088db6b8ae8af392710a453d51641ce1194' 
  AND token = 'sVWoopLgzEg4bQPPq0lAoggL+6hVsvMtKgEsT8kvFqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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