SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37b03ad6c2b67ad6055f53291f4466bd422000f41a85f0bfc4b2b329e4e2b6e7' 
  AND token = 'qox1oCZKUMD2CPOxKkGjJxSIR0zBqQU++gteCSoMIsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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