SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea46ee1eb3a4de8d69c9e0456c09ac9f640cb97bcb83afd371a3e055c3aac0c6' 
  AND token = 'aft+cVgtS4lTqv/5Y8D/57Bja9aVkZz+sxe4+JPs+1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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