SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd9b39434298ea2a0945f8ac713bb3ad6ab49910eef7a86f7d9b86687a002c60b' 
  AND token = 'RKtY43rKGBxOxYcTXEHNaVq2uxpz/YKMsihgO44wG9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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