SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7879748c399582a87871d9d778e3b9163e0e6670216dcc11a615e7998830ac5b' 
  AND token = 'gJK1Nn5IiMaRv4N/KEsbVphJaWT5tSr+IjUigCTtJrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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