SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5650e9e520d88e99744729eb4e99f6863301f66e0be7529e3695bde541df0e5' 
  AND token = 'EKkPMmeSWQN8ACMjLHa2PmmCDv6AvNooLrQIxDk/ats=' 
  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"
    }
  }
}