SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d3d381f34fa8e4e75040bfeec34551dee6aa1b9a4517484f15f6f0ae55ab102' 
  AND token = 'aCgdOkbDxfuAk0mYAaNcfQ6ysMjgUO8bhCXLKhJ47Kw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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