SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89e70b314e49983e2b3cc2b34953fefad41a8672a487cf844def898ed77485f8' 
  AND token = 'cfrfXRXQ29JLmtcxL1g1CDrAjdHDMCKWM3RumFZCqNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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