SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cffa6c7b6f8574a6cf4b06110c5b5999b433b24d2314437f792e46813e85036f' 
  AND token = '6ttM845jwomBhLyVwDAhKsafYKNzOIOYNp5rMd1qKxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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