SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a55cf63a44d092922d95f5690630ef0998138bf1ec6e1e9d1d7868bef1e1705f' 
  AND token = 'WNWfTzCYJcYLZTjhIhG7Sx3gXLlVq7J9xQNzzNdGuqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}