SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62a7a9b878ec52e00f71c4d5f162926825ae22aa5351736300744d3fd431680c' 
  AND token = 'JHLu+VCAMb11D/42Jz+0Dm/pKEpXom26FmIgcOA/qOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}