SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'dfe84e28ee489bc59d684d757472e82b7474a2091933adbfe4663883b4ec67b0' 
  AND token = 'B2w2O+oBf2L0gLhYMZqUcz8cBFwWYxoaz2O3zGjoqaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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