SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2756cfbe0cdde210bf5dc46f926f727e6dc78af7a6176415f8a40ede9fc514e2' 
  AND token = 'HNwdRwqg9fXpK46TGTTNGEPLaqCvPGHiNtrDlAdZB+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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