SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f66d764fca3b6057145655033278a624df37455dc89459c0b212f27791522f4' 
  AND token = 'S5TmwE6mMn7hCpV7S65X+1veXCXKbOvv3IOtDxusXDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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