SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '708842ed09f44efb8f61004fb3c33f97db75a10ec54c0f800197846f45eba46e' 
  AND token = 'ZvTYPEilc0w47mYhc46lsWri3VtxYxpvuoWpLbxqcNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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