SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b37701a655b5813ea4d1a387181cb673d90d0579fb61da70aab8daa696646882' 
  AND token = 'mgk/A6yraiaNaMKpCuvqjg2yZW4TypHH0/JmEK78bKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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