SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35524f56073fd22250d88ee54a17681e2e0893fcfc3875b73545f0361de90296' 
  AND token = 'I6VR6SoWBdWOhl3lI3loUJUFnKGXkdkiXus8X9XVfq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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