SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '502983fbd3a929f3c010f0b0589e242624e966eea5a8fe3cf175b1980675fb8c' 
  AND token = 'NcXxe6CCHOJeTjuoEd7UJUUNYQb1Isf+loIpJ/mIbJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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