SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cd5416a103838119f0016f6caee9e2fc4eb79f5864538688fb3110d532f9c5b' 
  AND token = 'AJQoK3UnrYPwAAx48gLMw4wSHc1tUUo8nms2rmx/9pQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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