SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e89113f1849bb5454e0e229e7a20532ffbc14276e69887143a69d228556a90c5' 
  AND token = '0L53v2LcLNWIiSGfpUycZPeeb9sXnSyGZhFMKi+qOVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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