SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89dd3d8f694d56e163683ef6e24b4fbba7057d1000e9854329999197fc255180' 
  AND token = 'jMRmYE1lCOw/Og6fGlumEDqVOMkSG7+qYuu8zq4GqpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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